Make $sample_permalink_html human-readable on Edit Post screen

Description

If the permalink contains words with non-latin characters (for example the permalink structure is /%category%/%postname%/ and the assigned category is non-English) the $sample_permalink_html, which is echoed by ​edit-form-advanced.php, is not human readable on Edit Post screen (below the title). The editable part of the permalink (the one that comes from the title of the post) is readable.

$sample_permalink_html should be urldecoded at some stage before echoed.

This is still an issue. It doesn't affect the post slug, just the rest of the permalink (eg. a when using a permastructure which includes the category name, and the post is in a category with punycode in its slug).

16496.3.patch​ urldecodes the permalink in the most appropriate place.